A group of octahydropyrazolo[3,4-g]quinolines is disclosed in Kornfeld and Bach, U.S. Pat. No. 4,198,415 issued Apr. 15, 1980, and in a divisional application thereof, U.S. Pat. No. 4,230,861 issued Oct. 28, 1980. Both intermediates and final products (Ia and Ib below) are disclosed therein. ##STR1## wherein R is H, C.sub.1 -C.sub.3 alkyl, allyl or benzyl, R.sup.1 is H or COOY and Y is C.sub.1 -C.sub.2 alkyl or phenyl-substituted C.sub.1 -C.sub.2 alkyl.
Compounds according to these structures (Ia or Ib) are final products where R.sup.1 is H and R is C.sub.1 -C.sub.3 alkyl or allyl, or are intermediates where R and R.sup.1 are H, where R is benzyl or where R.sup.1 is COOY wherein Y is defined as above. Where the compounds according to structures Ia and Ib are final products, they are useful as inhibitors of prolactin secretion and in the treatment of Parkinson's syndrome. Where the compounds are intermediates, they are converted by methods disclosed in the above patents to drugs which are useful in the inhibition of prolactin secretion and in the treatment of Parkinson's syndrome. Compounds according to structures Ia and Ib are to be found in U.S. Pat. No. 4,198,415 as compound IX in Reaction Scheme I or as compound XV in Reaction Scheme II where the single tautomer pictured represents both tautomers (as set forth therein). In both reaction schemes, a compound of formula II is converted to the final desired products Ia and Ib by the following generalized reaction scheme. ##STR2##
The reagent used to transform the 1-substituted 3-permissibly substituted-6-oxodecahydroquinoline (II) to the intermediate (III) is a dimethylformamide acetal such as dimethylformamide dimethylacetal. Compounds of structures II and III are also claimed in U.S. Pat. No. 4,230,861.